notification changes

-only send a notification when the person you follow creates a topic
-you still get a notification per post if you are following a topic
-changed notifications.push so that it sends the notifications over a
period of time, currently to 50 users per second
-optimized topics.notifyFollowers and
user.notifications.sendTopicNotification, they no longer query the
database for the topic and post data instead they get it as params
-you can no longer follow yourself :)
-changed mongo sortedSetRemove so that it doesn't use $in if there is
only a single value to remove

src/notifications.js

@@ -128,17 +128,58 @@ var async = require('async'),
 			return callback();
 		}
 
-		var websockets = require('./socket.io');
 		if (!Array.isArray(uids)) {
 			uids = [uids];
 		}
 
+		uids = uids.filter(function(uid) {
+			return parseInt(uid, 10);
+		});
+
+		if (!uids.length) {
+			return callback();
+		}
+
+		var done = false;
+		var start = 0;
+		var batchSize = 50;
+
+		setTimeout(function() {
+			async.whilst(
+				function() {
+					return !done;
+				},
+				function(next) {
+					var currentUids = uids.slice(start, start + batchSize);
+					if (!currentUids.length) {
+						done = true;
+						return next();
+					}
+					pushToUids(currentUids, notification, function(err) {
+						if (err) {
+							return next(err);
+						}
+						start = start + batchSize;
+
+						setTimeout(next, 1000);
+					});
+				},
+				function(err) {
+					if (err) {
+						winston.error(err.stack);
+					}
+				}
+			);
+		}, 1000);
+
+		callback();
+	};
+
+	function pushToUids(uids, notification, callback) {
 		var unreadKeys = [];
 		var readKeys = [];
 
-		uids.filter(function(uid) {
-			return parseInt(uid, 10);
-		}).forEach(function(uid) {
+		uids.forEach(function(uid) {
 			unreadKeys.push('uid:' + uid + ':notifications:unread');
 			readKeys.push('uid:' + uid + ':notifications:read');
 		});
@@ -163,13 +204,15 @@ var async = require('async'),
 			}
 
 			plugins.fireHook('action:notification.pushed', {notification: notification, uids: uids});
-			callback();
 
+			var websockets = require('./socket.io');
 			for(var i=0; i<uids.length; ++i) {
 				websockets.in('uid_' + uids[i]).emit('event:new_notification', notification);
 			}
+
+			callback();
 		});
-	};
+	}
 
 	Notifications.pushGroup = function(notification, groupName, callback) {
 		callback = callback || function() {};